Dynamic screwdriving production line based on workpiece movement

Abstract

The dynamic screw-tightening production line based on workpiece movement includes a conveyor platform, a robotic arm, and a workpiece fixing mold placed on the conveyor platform. Multiple robotic arms are provided on both sides of the conveyor platform and are spaced apart along the conveying direction of the conveyor platform. A compensation mechanism is installed at the end of the robotic arm, and the compensation mechanism is connected to a screw-tightening assembly. The robotic arm can drive the screw-tightening assembly to assemble with the workpiece fixing mold, and can adjust the angle position in real time as the workpiece fixing mold moves. Different from existing screw-tightening equipment and screw-tightening production line technology, the present invention adopts the form of assembling the screw-tightening assembly and the workpiece fixing mold. There is no need to shut down the conveyor belt. The screw tightening work is completed while the workpiece is moving. After completing the screw tightening of one workpiece, the work can continue to be carried out on the subsequent workpiece, realizing the continuous screw-tightening work and enabling fast and uninterrupted production.

Description

Technical Field

[0001] The present invention relates to the technical field of screw fastening of workpieces, in particular to a dynamic screw tightening production line based on workpiece movement. Background Art

[0002] When assembling products such as hair dryers, mobile phones, computers, and cars, it is necessary to tighten the screws of various components. The more traditional method is to tighten the screws manually. However, with the development of automation, in order to improve the efficiency of screw tightening and adapt to industrialized production, the existing technology usually uses automated equipment or automated assembly lines to tighten the screws for the product screw tightening process.

[0003] One type of automated equipment is a fixed workstation that cooperates with a fixed electric screwdriver to tighten screws. For example, the Chinese patent number is CN218657663U, a turntable multi-station multi-axis locking and automatic screw locking belt blanking machine. The screwing mechanism is combined with the product positioning mechanism. The turntable drives the workpieces fixed on each fixed table to move to the bottom of the screwing mechanism in turn to tighten the screws. Although it replaces manual operation and improves efficiency to a certain extent, this method has a slow production rhythm. The power device that drives the turntable to rotate needs to be constantly stopped during operation, and the turntable needs to be corrected after long-term use. Otherwise, a slight offset from the batch nozzle will make it impossible to tighten the screws normally, and the continuity of the screw tightening work is poor.

[0004] The assembly line screw driving method uses a fixed workstation with a movable robotic arm to tighten the screws. It is also the most commonly used method on the market. For example, the Chinese patent number CN206811450U is a robot screw driving machine that uses a four-axis robot to cooperate with the assembly line. The product is placed on the first section of the assembly line and moved to the middle assembly line. The assembly line is stopped and the product is stationary. The four-axis robot identifies the threaded hole and tightens the screw. This method requires high-precision identification of the position of the threaded hole. The identification and positioning takes a long time and requires real-time positioning of the threaded hole. Position, and the product is stationary, which is equivalent to using a fixed work station. Although the robot is more flexible, the opening and closing of the assembly line and the detection and sensing of each section of the assembly line take up more time and are more cumbersome. Moreover, a set of assembly lines can only tighten the screws of a single product, and the continuity of screw tightening cannot be guaranteed. The overall production efficiency is still relatively low, and in actual application, the absolute stability of the assembly line must be guaranteed. When the working environment is relatively harsh, due to the work of high-power electrical appliances such as motors, slight vibrations will cause the electric screwdriver to be unable to align with the threaded hole, and may even cause damage to the electric screwdriver and the robotic arm. Summary of the Invention

[0005] In order to solve the problems existing in the existing screw-driving equipment and production lines mentioned in the above background technology, the present invention provides a dynamic screw-driving production line based on workpiece movement.

[0006] The technical solutions of the present invention are as follows:

[0007] A dynamic screwdriving production line based on workpiece movement includes a conveyor platform, a robotic arm, and a workpiece fixing mold placed on the conveyor platform. The robotic arm is provided in multiple groups on both sides of the conveyor platform and is arranged at intervals along the conveying direction of the conveyor platform. A compensation mechanism is installed at the end of the robotic arm, and the compensation mechanism is connected to the screwdriving assembly.

[0008] The robotic arm can drive the screw-tightening assembly to assemble with the workpiece fixing mold, and can adjust the angle position in real time as the workpiece fixing mold moves;

[0009] The compensation mechanism includes a compensation frame mounted at the end of the robotic arm, wherein a plurality of fixed columns are mounted perpendicular to the two side frames in the compensation frame, and a plurality of compensation units are slidably arranged between each two fixed columns. The screw assembly is connected to the compensation unit and can slide along with the compensation unit in a direction parallel to the fixed columns or perpendicular to the plane where the plurality of fixed columns are located;

[0010] A binocular camera is provided on one side of the bottom of the compensation frame close to the screw-tightening assembly, and the lowest end of the binocular camera is higher than the lowest end of the compensation frame. Coarse positioning marks are dispersedly arranged on the upper surface of the workpiece fixing mold. The coarse positioning marks can be used for the binocular camera to perform initial recognition at a distance of 10cm-120cm from the workpiece fixing mold. Fine positioning marks are also centrally arranged on the workpiece fixing mold. The fine positioning marks can be used for the binocular camera to perform secondary recognition at a distance of less than 10cm from the workpiece fixing mold to complete the assembly of the screw-tightening assembly and the workpiece fixing mold.

[0011] Specifically, several workpiece fixing molds carrying workpieces are placed on the conveyor table, and the conveyor table drives the workpiece fixing mold to move. The binocular camera first performs an initial recognition of the coarse positioning mark on the workpiece fixing mold. Here, the robotic arm is first positioned to the approximate position of the workpiece fixing mold, and then the robotic arm drives the screw tightening assembly to move downward. The binocular camera performs a second recognition of the fine positioning mark, and the robotic arm moves synchronously with the workpiece fixing mold to recognize the precise position. The screw tightening assembly is assembled with the workpiece fixing mold, and the screw tightening assembly is controlled to tighten the screws on the workpiece. After completion, the robotic arm is lifted and re-identifies the next workpiece fixing mold, and continues the subsequent screw tightening work of the workpiece. In the process of fixing the workpiece mold, the workpiece will vibrate due to the influence of the motor or other equipment of the conveyor table. The camera recognition and adjustment of the tracking position alone cannot respond to the robotic arm in time for adjustment. The compensation unit slides in the direction parallel to the fixed column or perpendicular to the plane where the multiple fixed columns are located to compensate for the displacement in two directions and eliminate the vibration.

[0012] To facilitate installation of the compensation unit and achieve displacement compensation in both directions, the compensation frame is designed as a hollow square frame, with the end of the robotic arm positioned perpendicularly to the frame's upper and lower frames and multiple fixing posts. The hollow square frame design means the compensation frame has front and rear end faces, and the vertical alignment of the upper and lower frames with the end of the robotic arm ensures that both the end of the robotic arm and the compensation frame face downward when the screw assembly engages the workpiece-securing mold, facilitating their interaction.

[0013] In order to make the compensation unit achieve balance during compensation work and better play the role of displacement compensation, four fixed columns are provided. When the screw assembly is working, they are located in the same vertical plane and arranged horizontally. The upper two are a group and the lower two are a group. The distance between the two groups is smaller than the distance between the two fixed columns in the same group, which is convenient for the subsequent installation of the I-frame, reduces the overall area of ​​the I-frame, and then reduces the overall weight of the compensation mechanism. Two groups of compensation units are installed between the two fixed columns of each group. There are four groups of compensation units in total, which are distributed in a field shape within the compensation frame and are symmetrically arranged up and down and left and right. They can play a balancing role during compensation and improve the stability of the compensation mechanism.

[0014] Furthermore, each set of the compensation units includes a mounting bracket disposed between two fixed columns, with first optical axis sliders mounted on the upper and lower ends of the mounting bracket, which are slidably mounted with the fixed columns. The first optical axis slider can slide along the fixed columns to eliminate displacement along the fixed columns due to vibration. Second optical axis sliders are mounted on the left and right ends of the mounting bracket, and the sliding holes of the second optical axis sliders extend in a direction perpendicular to the plane in which the multiple fixed columns are located. The second optical axis sliders are used to mount other components of the compensation unit, eliminating displacement along a direction perpendicular to the plane in which the multiple groups of fixed columns are located. Through displacement compensation in two directions, vibration generated by the end of the screwdriving assembly is converted into displacement in two directions, replacing the original rigid connection between the screwdriving assembly and the robotic arm, ensuring the smooth progress of the screwdriving work and indirectly protecting the normal use of the robotic arm.

[0015] Based on the above structure, the mounting frame is further configured as a hollow square frame, with the four faces of the mounting frame arranged parallel to the four faces of the compensation frame. The first optical axis slider and the second optical axis slider are respectively mounted at the midline of the four faces of the mounting frame. The hollow square frame means that the mounting frame has no front or rear end faces, but only four end faces, top, bottom, left, and right. The hollow configuration further reduces the overall weight of the compensation mechanism. The first and second optical axis sliders are both mounted at the midline to improve the stability of the mounting frame, preventing it from deflecting in its natural state, thereby preventing the entire screw-tightening assembly from shaking. It also ensures that all second optical axis sliders between the two fixed columns of each group are in the same straight line, facilitating the installation of the sliding column and the I-beam.

[0016] To connect the screw assembly to the compensation mechanism and eliminate vibration at the end of the screw assembly, a sliding post is slidably installed in the sliding hole of the second optical axis slider. Both ends of the sliding post are connected to an I-beam. The two crossbeams of the I-beam are arranged parallel to the fixed posts and are respectively connected to the corresponding sliding posts between the two sets of fixed posts. The screw assembly is mounted on the side of one of the I-beams. Each second optical axis slider is equipped with a sliding post, with two sets of sliding posts arranged in a straight line. The I-beam has two crossbeams that can connect with the two sets of sliding posts. The vertical beam of the I-beam can also be used to install the electric ball screw of the screw assembly. If these components can be installed, the I-beam will further reduce the weight of the entire compensation mechanism.

[0017] Furthermore, both sides of the first and second optical axis sliders are connected to return springs, which are respectively mounted on the fixed column and the sliding column and fixedly connected to both. The return springs on both sides of the first optical axis slider can ensure that the center of the plane formed by the four mounting brackets coincides with the center of the compensation frame, while the return springs on both sides of the second optical axis slider can ensure that the center of the sliding rod in its natural state coincides with the center of the second optical axis slider. The return springs in both locations can, on the one hand, keep the compensation unit in a static state when no vibration is generated, thereby accelerating the coordination between the screw tightening assembly and the workpiece fixing mold. On the other hand, they can reset the first optical axis slider and the sliding column after the displacement compensation action is completed.

[0018] Furthermore, the screw-driving assembly includes an electric ball screw installed on the vertical beam of the I-frame, which is in a vertical state when working. The electric ball screw is located above the binocular camera. The lifting end of the electric ball screw is installed with an electric screwdriver module. The number and position of the electric screwdrivers in the electric screwdriver module are consistent with the number and position of the threaded holes in the workpiece. The electric ball screw is installed on the vertical beam of the I-frame, just in the middle position, and the binocular camera is set at its bottom. After the recognition work is carried out, the screw-driving assembly is assembled with the workpiece fixing mold. At this time, the electric screw of the electric screwdriver module is just opposite to the threaded hole of the workpiece. The electric ball screw structure drives it to move downward to perform the screw-driving work. The setting and the middle position can ensure the stability of the electric screwdriver module when it descends and rises.

[0019] On the basis of the above structure, the screw-driving assembly further includes two limit columns mounted on both sides of the I-shaped frame, and the electric screwdriver module is slidably connected to the limit columns; the limit columns are connected to the two beams of the I-shaped frame through mounting seats, the lower ends of the limit columns pass through the mounting seats at the bottom and the lowest ends are lower than the bottom end of the compensation frame, the bottom ends of the limit columns are connected to positioning columns, and the workpiece fixing mold is provided with two positioning holes adapted to the positioning columns, and the positioning columns can be inserted into the positioning holes. The two limit columns can be mounted on the two beams of the I-shaped frame through two sets of mounting seats, and are located on both sides of the electric ball screw. On the one hand, the limit columns limit the electric screwdriver module so that it can slide up and down, and on the other hand, the bottom is used to install the positioning columns. The assembly of the positioning columns and the positioning holes realizes the assembly of the screw-driving assembly and the workpiece fixing mold, and the height setting of the lowest end of the limit columns is to ensure that after the positioning columns and the positioning holes are assembled, there is a certain gap between the compensation frame and the workpiece fixing mold to prevent collisions.

[0020] To speed up the assembly of the positioning post and the positioning hole, the positioning post is an electromagnet, and a cylindrical iron block for the electromagnet to attract is located within the positioning hole. During identification and assembly, when the positioning post approaches the positioning hole, the electromagnet is energized, allowing it to quickly attract the cylindrical iron block at the bottom of the positioning hole, greatly speeding up the assembly process and improving the efficiency of the screwdriving process.

[0021] The beneficial effects of the present invention are as follows: the present invention is a dynamic screw-tightening production line based on the movement of the workpiece. Different from the existing screw-tightening equipment and screw-tightening production line technology, the present invention adopts the form of assembling a screw-tightening component and a workpiece fixing mold. There is no need to shut down the conveyor belt. The screw tightening work is completed in the process of the workpiece moving. After completing the screw tightening of one workpiece, the subsequent workpiece can continue to be tightened, thereby realizing the continuous screw tightening work and enabling rapid and uninterrupted production.

[0022] Furthermore, the first optical axis slider adopting the compensation mechanism can slide along the fixed column, which can eliminate the displacement in the direction of the fixed column caused by vibration. The sliding column and the I-beam cooperate with the second optical axis slider to eliminate the displacement in the direction perpendicular to the plane where the multiple groups of fixed columns are located. Through displacement compensation in two directions, the vibration generated at the end of the screw-tightening assembly is converted into displacement in two directions, replacing the original rigid connection between the screw-tightening assembly and the robotic arm, ensuring the smooth progress of the screw-tightening work and indirectly protecting the normal use of the robotic arm.

[0023] By assembling the positioning column and the positioning hole, the present invention can identify the position of the threaded hole with only two identifications, without the need for real-time positioning and tracking of the threaded hole, thereby reducing the recognition accuracy of the threaded hole on the workpiece on the assembly line and expanding the scope of application. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] By reading the detailed description of the preferred embodiment below, the solutions and advantages of the present application will become clear to those skilled in the art. The accompanying drawings are only for illustrating the preferred embodiment and are not to be considered as limiting the present invention.

[0025] In the attached figure:

[0026] Figure 1 This is the general assembly drawing of the present invention;

[0027] Figure 2 for Figure 1 Enlarged view of point A;

[0028] Figure 3 This is a structural diagram of the first part of the present invention;

[0029] Figure 4 This is a structural diagram of the second part of the present invention;

[0030] The components represented by the reference numerals in the figure are:

[0031] 1. Conveyor table; 2. Robotic arm; 3. Workpiece fixing mold; 31. Positioning hole; 32. Workpiece placement slot; 4. Compensation mechanism; 41. Compensation frame; 42. Fixed column; 43. Mounting frame; 44. First optical axis slider; 45. Second optical axis slider; 46. Sliding column; 47. I-beam; 48. Reset spring; 5. Screw tightening assembly; 51. Electric ball screw; 52. Electric screwdriver module; 53. Limit column; 54. Mounting seat; 55. Positioning column; 56. Electric screwdriver fixing plate; 6. Binocular camera; 7. Coarse positioning mark; 8. Fine positioning mark; 9. Base; 10. Z-shaped frame. DETAILED DESCRIPTION

[0032] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. It should be noted that these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art. The present disclosure can be implemented in various forms and should not be limited by the embodiments described herein.

[0033] Example

[0034] Dynamic screwdriving production line based on workpiece movement, such as Figure 1 As shown, it includes a conveying platform 1, a robotic arm 2 and a workpiece fixing mold 3 placed on the conveying platform 1. The conveying platform 1 adopts a synchronous belt assembly line. The workpiece fixing mold 3 is provided with a workpiece placement groove 32 adapted to the shape of the workpiece, which is used to place the workpiece to be screwed. The workpiece fixing mold 3 is selected according to the processing of different workpieces. Several workpiece fixing molds 3 are placed on the conveying platform 1 at a certain interval, and the conveying platform 1 drives the workpiece fixing mold 3 to move.

[0035] Furthermore, multiple groups of robotic arms 2 are provided on both sides of the conveying table 1, and are arranged at intervals along the conveying direction of the conveying table 1. The robotic arms 2 adopt a six-axis design, and the bottom of the robotic arms 2 is installed on the base 9, and the base 9 is placed on the ground. The distance between the two robotic arms 2 on the same side is consistent, and the installation interval and the total number of installations are set according to the length of the conveying table 1. By setting the moving speed of the conveying table 1, the interval of the workpiece fixing mold 3, and the interval and number of the robotic arms 2, the effect of non-stop assembly line and dynamic tightening of screws by the robotic arms 2 is achieved.

[0036] Furthermore, a compensation mechanism 4 is installed at the end of the robot arm 2, such as Figure 2As shown, the compensation mechanism 4 is connected to a screw assembly 5, and the robotic arm 2 can drive the screw assembly 5 to assemble with the workpiece fixing mold 3. After assembly, the robotic arm 2 can adjust the angular position in real time as the workpiece fixing mold 3 moves. The specific assembly is mainly achieved by two positioning columns 5 provided on the screw assembly 5 and the positioning hole 31 provided on the workpiece fixing mold 3. The positioning columns 55 and the positioning holes 31 are both set to be cylindrical, and the shapes and sizes of the two are adapted. The robotic arm 2 drives the positioning columns 55 to be inserted into the positioning holes 31 to realize the assembly of the screw assembly 5 and the workpiece fixing mold 3. In order to ensure that the assembly can be carried out quickly and save the time required for assembly, the positioning columns 55 are set to be electromagnets, and a cylindrical iron block is set at the bottom of the positioning hole 31. When the electromagnet approaches the positioning hole 31, the electromagnet is energized and can be quickly adsorbed on the cylindrical iron block in the positioning hole 31. On the one hand, the assembly speed is improved, and on the other hand, the assembly of the screw assembly 5 and the workpiece fixing mold 3 can be made more stable, avoiding the shaking of the two when the workpiece fixing mold 3 moves, thereby ensuring the stability of the device itself during the screwing operation.

[0037] Therefore, in order to realize the assembly of the positioning column 55 and the positioning hole 31, the assembly work is specifically realized by a binocular camera 6 arranged at the bottom of the compensation mechanism 4. The binocular camera 6 is installed on the side close to the screw-tightening assembly 5, and the lowest end of the binocular camera 6 is higher than the lowest end of the compensation frame 41 to prevent the binocular camera 6 from colliding with the workpiece fixing mold 3 at the bottom during assembly. The binocular camera 6 is electrically connected to the control end of the robotic arm 2. The binocular camera 6 can transmit a signal to the control end, and the control end controls the movement of the robotic arm 2. Coarse positioning marks 7 are dispersed on the upper surface of the workpiece fixing mold 3. The coarse positioning marks 7 can be used for the initial recognition of the binocular camera 6 at a distance of 10cm-120cm from the workpiece fixing mold 3. The initial recognition is to first perform long-distance recognition of the workpiece fixing mold 3 to determine the approximate position of the workpiece fixing mold 3. The coarse positioning marks 7 are four circular labels with a larger diameter, which are dispersed on both sides of the workpiece placement slot 32. Coarse positioning is used when the binocular camera 6 searches for the workpiece and controls the robotic arm 2 to move quickly to the workpiece position.

[0038] Furthermore, the workpiece fixing mold 3 is also centrally arranged with precise positioning marks 8. The precise positioning marks 8 are used for secondary identification at close range. They are also four circular labels, but with a smaller diameter. They are centrally arranged above the workpiece placement slot 32 and in the middle of the two positioning holes 31. The precise positioning marks 8 can be used for secondary identification by the binocular camera 6 when the binocular camera 6 is less than 10 cm away from the workpiece fixing mold 3. When the binocular camera 6 controls the robot arm 2 to assemble the positioning column 55 with the positioning hole 31 and the robot arm 2 moves synchronously with the workpiece, precise positioning is used to achieve synchronous movement of the screw tightening assembly 5 and the workpiece fixing mold 3, and timely adjustment of the angle. After the assembly work is completed, the screw tightening assembly 5 starts to tighten the screws on the moving workpiece.

[0039] In addition, the binocular camera 6 is installed at the bottom of the compensation frame 41 through the Z-shaped frame 10, so that the binocular camera 6 protrudes from the side of the compensation frame 41 close to the screw-tightening assembly 5, and the binocular camera 6 is raised to prevent the binocular camera 6 from colliding with the workpiece fixing mold 3 during the recognition process. The recognition end of the binocular camera 6 and the line connecting the centers of the two positioning columns 55 are in the same plane and are located in the middle of the two positioning columns 55, making the recognition faster and the two sides more balanced.

[0040] Combine Figure 3 and Figure 4When the workpiece is moving, the screwing work is performed. Due to the operation of multiple motors and the unevenness of the assembly line, the workpiece fixing mold 3 will vibrate, which will cause the electric screwdriver to be unable to align with the threaded hole and may even cause damage to the electric screwdriver and the robotic arm 2. Therefore, the screwing assembly 5 is connected to the end of the robotic arm 2 through the compensation mechanism 4. Specifically, the compensation mechanism 4 includes a compensation frame 41 installed at the end of the robotic arm 2. The compensation frame 41 is set as a hollow square frame. The hollow square frame means that the compensation frame 41 is not provided with front and rear end faces, but only with four upper, lower, left and right frames, which is convenient for installing the compensation unit and the sliding of the compensation unit, and the end of the robotic arm 2 is perpendicular to the upper and lower frames of the compensation frame 41 to ensure that when the screwing assembly 5 is matched with the workpiece fixing mold 3, the end of the robotic arm 2 and the compensation frame 41 are both vertically downward, which is convenient for the cooperation between the two. A plurality of fixed Columns 42, in this embodiment, are specifically provided with four, and the fixed columns 42 are arranged perpendicularly to the end of the robotic arm 2, ensuring the sliding direction of the compensation unit. When the screw-tightening assembly 5 is working, it is located in the same vertical plane and is arranged horizontally. The upper two are a group, and the lower two are a group. The spacing between the two groups is smaller than the distance between the two fixed columns 42 in the same group. Multiple groups of compensation units are slidingly arranged between every two fixed columns 42. In this embodiment, two groups of compensation units are installed between the two fixed columns 42 of each group, for a total of four groups. The screw-tightening assembly 5 is connected to the compensation unit and can slide along the direction parallel to the fixed columns 42 or perpendicular to the plane direction of the multiple fixed columns 42. When the workpiece vibrates, the force can be transmitted to the compensation unit through the screw-tightening assembly 5, decomposed into displacement along the direction of the fixed column 42 and the direction perpendicular to the fixed column 42, driving the screw-tightening assembly 5 to produce a small displacement to eliminate the vibration.

[0041] The specific compensation unit realizes the vibration compensation work through the following structure. Each group of compensation units includes a mounting frame 43 arranged between two fixed columns 42. Since there are four groups of compensation units in total, four corresponding mounting frames 43 are arranged, and each mounting frame 43 is a hollow square frame. The hollow square frame means that the mounting frame 43 is not provided with front and rear end faces, but only includes four end faces of top, bottom, left and right. The hollow setting also further reduces the overall weight of the compensation mechanism 4, and the four faces of the mounting frame 43 are respectively arranged parallel to the four faces of the compensation frame 41. The upper and lower ends of the mounting frame 43 are equipped with a first optical axis slider 44 that is slidably arranged with the fixed column 42. The first optical axis slider 44 can slide along the fixed column 42 to eliminate the vibration caused by the vibration along the direction of the fixed column 42. Displacement, the left and right ends of the mounting frame 43 are equipped with second optical axis sliders 45, and the extension direction of the sliding hole of the second optical axis slider 45 is perpendicular to the plane where the multiple fixed columns 42 are located. The second optical axis slider 45 is set to install other components of the compensation unit, which can eliminate the displacement caused by the displacement along the plane direction perpendicular to the multiple groups of fixed columns 42. The first optical axis slider 44 and the second optical axis slider 45 are respectively installed at the center line of the four surfaces of the mounting frame 43. In order to improve the stability of the mounting frame 43, prevent it from offsetting in a natural state, and then prevent the entire screw tightening assembly 5 from shaking, and it can ensure that all the second optical axis sliders 45 between the two fixed columns 42 of each group are in the same straight line, which is convenient for the installation of the sliding column 46 and the I-beam 47.

[0042] Furthermore, a screw assembly 5 is installed on one side of the compensation unit, and a sliding column 46 is slidingly provided in the sliding hole of the second optical axis slider 45. A sliding column 46 is slidably installed in the sliding hole of each second optical axis slider 45. The sliding column 46 can slide back and forth along the plane direction perpendicular to the multiple fixed columns 42. Two groups of sliding columns 46 arranged in a straight line are formed in the upper and lower parts of the compensation frame 41. An I-frame 47 is connected to both ends of the sliding column 46. The two crossbeams of the I-frame 47 are respectively installed with the two groups of sliding columns 46. The two crossbeams of the I-frame 47 are parallel to the fixed columns 42. The screw assembly 5 is installed on the side of one of the I-frames 47. When the screw assembly 5 vibrates, on the one hand, it slides along the plane direction perpendicular to the fixed column 42 through the I-frame 47 and the sliding column 46. On the other hand, it can transmit force to the first optical axis slider 44 through the mounting frame 43, and then slide along the direction of the fixed column 42.

[0043] Furthermore, return springs 48 are connected to both sides of the first optical axis slider 44 and the second optical axis slider 45. The return springs 48 are respectively mounted on the fixed column 42 and the sliding column 46, with one end fixedly connected to both, thereby supporting the first optical axis slider 44 and the sliding column 46. The return springs 48 on both sides of the first optical axis slider 44 ensure that the plane formed by the four mounting brackets 43 is located in the middle position of the compensation frame 41. The return springs 48 on both sides of the second optical axis slider 45 ensure that the sliding rod 45 is located in the middle position of the sliding rod 46 when in a natural state. The return springs 48 at both locations can, on the one hand, keep the compensation unit in a static state during the recognition process of the binocular camera 6 and when no vibration is generated, thereby accelerating the cooperation between the screw tightening assembly 5 and the workpiece fixing mold 3 and ensuring the stable operation of the screw tightening assembly 5. On the other hand, they can reset the first optical axis slider 44 and the sliding column 46 after the displacement compensation action is completed.

[0044] In the present invention, combined with the Figure 3 The screw-tightening assembly 5 includes an electric ball screw 51 installed at the vertical beam of the I-frame 47, ensuring that the electric ball screw 51 is in the middle position of the I-frame 47. The screw can be driven by a power device such as a motor, and the screw can be connected to the two crossbeams of the I-frame 47 through a mounting seat 54. When it is working, it is in a vertical state. The electric ball screw 51 is above the displacement binocular camera 6. The lifting end of the electric ball screw 51 is installed with an electric screw fixing plate 56, and an electric screw module 52 is installed in the electric screw fixing plate 56. The number and position of the electric screws in the electric screw module 52 are consistent with the workpiece thread. The number and position of the holes remain consistent. The electric screwdriver fixing plate 56 can be replaced according to the shape of the workpiece to adapt to the screw tightening of different workpieces. The vertical distance from the output end of the electric screwdriver to the vertical line where the positioning column 55 is located is consistent with the vertical distance from the threaded hole of the workpiece to the vertical line where the positioning hole 31 is located. This ensures that when the positioning column 55 is inserted into the positioning hole 31, the output ends of each electric screwdriver in the electric screwdriver module 52 are aligned one by one with the positions of each threaded hole on the workpiece. In the next step, the electric ball screw 51 can be operated to drive the electric screwdriver fixing plate 56 to move downward to the threaded hole position, and the electric screwdriver can be started to tighten the screws.

[0045] In addition, the screw tightening assembly 5 also includes two limit columns 53 installed on both sides of the I-frame 47. The limit columns 53 are connected to the two cross beams of the I-frame 47 through the mounting seats 54. The lower ends of the limit columns 53 pass through the mounting seats 54 at the bottom and the lowest ends are lower than the bottom ends of the compensation frame 41. The limit columns 53 have two functions. On the one hand, the limit columns 53 between the two mounting seats 54 are used to limit the electric screwdriver fixing plate 56, and the electric screwdriver fixing plate 56 is slidingly set with it. On the other hand, the bottom ends of the limit columns 53 are used to install the positioning columns 55. When assembling the screw tightening assembly 55 and the workpiece fixing mold 3, the limit columns 53 drive the positioning columns 55 to move to the positioning holes 31, and then the electromagnet is energized to realize the assembly of the two.

[0046] It should be noted that the electric screwdriver has its own torque measurement. When the specified torque is reached, the electric screwdriver stops working, the electric ball screw 51 drives the electric screwdriver to move upward, the electromagnet is powered off, and the end of the robotic arm 2 moves upward as a whole to return to the initial position and enter the next cycle.

Claims

1. Dynamic screw-tightening production line based on workpiece movement, characterized by: The invention comprises a conveying platform (1), a mechanical arm (2), and a workpiece fixing mold (3) placed on the conveying platform (1); the mechanical arm (2) is provided in multiple groups on both sides of the conveying platform (1) and is arranged at intervals along the conveying direction of the conveying platform (1); a compensation mechanism (4) is installed at the end of the mechanical arm (2); and the compensation mechanism (4) is connected to a screw assembly (5); The mechanical arm (2) is capable of driving the screw-tightening assembly (5) to assemble with the workpiece fixing mold (3), and is capable of adjusting the angular position in real time as the workpiece fixing mold (3) moves; The compensation mechanism (4) comprises a compensation frame (41) mounted at the end of the robotic arm (2), a plurality of fixed columns (42) being mounted in the compensation frame (41) perpendicular to the two side frames, a plurality of compensation units being slidably arranged between every two fixed columns (42), the screw assembly (5) being connected to the compensation unit and being able to slide along with the compensation unit in a direction parallel to the fixed columns (42) or perpendicular to the plane where the plurality of fixed columns (42) are located; A binocular camera (6) is provided on one side of the bottom of the compensation frame (41) close to the screw assembly (5), and the lowest end of the binocular camera (6) is higher than the lowest end of the compensation frame (41); coarse positioning marks (7) are dispersedly arranged on the upper surface of the workpiece fixing mold (3); the coarse positioning marks (7) can be used for the binocular camera (6) to perform initial recognition at a distance of 10 cm to 120 cm from the workpiece fixing mold (3); fine positioning marks (8) are also centrally arranged on the workpiece fixing mold (3); the fine positioning marks (8) can be used for the binocular camera (6) to perform secondary recognition at a distance of less than 10 cm from the workpiece fixing mold (3) to complete the assembly of the screw assembly (5) and the workpiece fixing mold (3); The compensation frame (41) is configured as a hollow square frame, and the end of the robotic arm (2) is vertically arranged with the upper and lower frames of the compensation frame (41) and a plurality of fixing columns (42); The fixing columns (42) are provided with four in total, and are located in the same vertical plane when the screw assembly (5) is working, and are arranged horizontally, with the upper two columns forming a group and the lower two columns forming a group, and the distance between the two groups is smaller than the distance between the two fixing columns (42) in the same group, and two groups of compensation units are installed between the two fixing columns (42) in each group; Each group of the compensation units includes a mounting frame (43) disposed between two fixed columns (42), and a first optical axis slider (44) slidably disposed with the fixed columns (42) is mounted on the upper and lower ends of the mounting frame (43); Second optical axis sliders (45) are installed at the left and right ends of the mounting frame (43), and the extending direction of the sliding hole of the second optical axis slider (45) is perpendicular to the plane where the multiple fixing columns (42) are located.

2. The dynamic screw-tightening production line based on workpiece movement according to claim 1 is characterized in that: The mounting frame (43) is a hollow square frame, and the four surfaces of the mounting frame (43) are respectively arranged in parallel with the four surfaces of the compensation frame (41), and the first optical axis slider (44) and the second optical axis slider (45) are respectively installed at the center lines of the four surfaces of the mounting frame (43).

3. The dynamic screw-tightening production line based on workpiece movement according to claim 2 is characterized in that: A sliding column (46) is slidably provided in the sliding hole of the second optical axis slider (45), and both ends of the sliding column (46) are connected to an I-shaped frame (47); The two crossbeams of the I-shaped frame (47) are arranged parallel to the fixed columns (42) and are respectively connected to the corresponding sliding columns (46) between the two groups of fixed columns (42). The screw-tightening assembly (5) is installed on the side of one of the I-shaped frames (47).

4. The dynamic screw-tightening production line based on workpiece movement according to claim 3 is characterized in that: Both sides of the first optical axis slider (44) and the second optical axis slider (45) are connected with a return spring (48), and the return spring (48) is respectively mounted on the fixed column (42) and the sliding column (46) and fixedly connected to the two.

5. The dynamic screw-driving production line based on workpiece movement according to claim 3 is characterized in that: The screw-tightening assembly (5) includes an electric ball screw (51) mounted on a vertical beam of an I-shaped frame (47), which is in a vertical state when in operation, and the electric ball screw (51) is located above the binocular camera (6); An electric screwdriver module (52) is installed at the lifting end of the electric ball screw (51), and the number and position of the electric screwdrivers in the electric screwdriver module (52) are consistent with the number and position of the threaded holes in the workpiece.

6. The dynamic screw-driving production line based on workpiece movement according to claim 5 is characterized in that: The screw-tightening assembly (5) further includes two limiting columns (53) mounted on both sides of the I-shaped frame (47), and the electric screwdriver module (52) is slidably connected to the limiting columns (53); The limiting column (53) is connected to the two crossbeams of the I-shaped frame (47) through the mounting seat (54); the lower end of the limiting column (53) passes through the mounting seat (54) at the bottom and the lowest end is lower than the bottom end of the compensation frame (41); the bottom end of the limiting column (53) is connected to a positioning column (55); two positioning holes (31) adapted to the positioning columns (55) are provided on the workpiece fixing mold (3); the positioning columns (55) can be inserted into the positioning holes (31).

7. The dynamic screw-driving production line based on workpiece movement according to claim 6 is characterized in that: The positioning column (55) is an electromagnet, and a columnar iron block for adsorption by the electromagnet is arranged in the positioning hole (31).

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